Irritable male syndrome
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Irritable male syndrome (IMS), is a term coined by a doctor working at the Medical Research Council's Human Reproductive Sciences Unit, in Edinburgh, Scotland, who studied the mating cycle of Soay sheep. During the autumn, the rams' testosterone levels soared and they mated. In the winter, testosterone levels fell and they stopped mating. As their testosterone levels were falling, rams became nervous and withdrawn, striking out irrationally. Dr. Lincoln has observed these same changes in behavior in red deer, reindeer, and Indian elephants. Thus the term covers symptoms thought to be caused by a drop in testosterone levels in male mammals that have well-defined mating cycles. IMS is a striking feature in mammals with seasonal breeding patterns; it manifests at the end of the mating season.
The term was alternatively defined by Jed Diamond, an author and lay person, as a state of hypersensitivity, anxiety, frustration, and anger that occurs in male human beings; Diamond considered it to be part of the andropause, which he defined as hormonal, physiological, and chemical changes that occur in all middle-aged men. Diamond felt that Stress is a common trigger, especially when combined with rapid hormone changes later in life. 
- The irritable male syndrome by Lincoln GA. MRC Human Reproductive Sciences Unit, Centre for Reproductive Biology, Edinburgh, UK, Reprod Fertil Dev 2001;13(7-8):567–76.
- The Irritable Male Syndrome: Managing the Four Key Causes of Depression and Aggression, Jed Diamond, Rodale, 2004, ISBN 1-57954-798-2,ISBN 978-1-57954-798-1, page 7
- Fields, S. (n.d.). Male PMS and Low Testosterone Levels Linked. (archive.org mirror)